Pushing the limits of flow strength in diamond

TL;DR

This paper demonstrates that shock-compressed nano-polycrystalline diamond can reach unprecedented flow strength of over 107 GPa through stacking fault-mediated strengthening, revealing new mechanisms for material strength under extreme conditions.

Contribution

The study combines femtosecond X-ray diffraction and molecular dynamics simulations to identify stacking fault-mediated strengthening as a key mechanism in ultra-high strength diamond.

Findings

Peak flow strength of 107+-5 GPa achieved

Mechanism involves stacking fault-mediated strengthening

Extreme conditions unlock unusual material strength

Abstract

Extreme pressures and temperatures create conditions that allow even hard and brittle materials to deform plastically. Despite extensive research, the upper limits of flow strength, the resistance to plastic flow, remain uncertain, and the mechanisms driving deformation at the relevant stresses are a subject of debate. Using femtosecond in situ X-ray diffraction experiments and large-scale molecular dynamics simulations, we demonstrate that stacking fault-mediated strengthening enables shock-compressed nano-polycrystalline diamond to achieve a peak flow strength of 107+-5 GPa at a stress of 227+-8 GPa. Our findings show that extreme conditions can unlock unusual strength via mechanisms that can be used as design tools in targeted applications.